/*
 * R : A Computer Language for Statistical Data Analysis
 * Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
 * Copyright (C) 1997--2008  The R Development Core Team
 * Copyright (C) 2003, 2004  The R Foundation
 * Copyright (C) 2010 bedatadriven
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.renjin.primitives.special;

import org.renjin.eval.Context;
import org.renjin.sexp.Environment;
import org.renjin.sexp.FunctionCall;
import org.renjin.sexp.Null;
import org.renjin.sexp.PairList;
import org.renjin.sexp.SEXP;
import org.renjin.sexp.SpecialFunction;

public class WhileFunction extends SpecialFunction {

  public WhileFunction() {
    super("while");
  }
  
  @Override
  public SEXP apply(Context context, Environment rho, FunctionCall call, PairList args) {
    SEXP condition = args.getElementAsSEXP(0);
    SEXP statement = args.getElementAsSEXP(1);

    while(asLogicalNoNA(context, call, context.evaluate( condition, rho))) {

      try {

        context.evaluate( statement, rho);

      } catch(BreakException e) {
        break;
      } catch(NextException e) {
        // next loop iteration
      }
    }
    context.setInvisibleFlag();
    return Null.INSTANCE;
  }
}
